Knock diesel

Quieter operation (no ignition delay or diesel knock lower peak cylinder pressures and temperatures). 

Diesel knock the result of a delayed period of ignition and accumulated diesel fuel in the engine. 

In the Diesel engine, a higher compression ratio can be achieved, up to about 18, before knock presents a problem, and the fuel is injected into the combustion chamber near tire end of the compression stroke as a spray. The... 

In the case of diesel fuel, an important property that defines the fuel quality is the cetane number (CN). Fuels with low-CN have poor ignition quality (i.e. knocking, noise, PM emissions) and make starting the engine difficult on cold days.6,7 It is well known that CN is lowest for PAHs and highest for w-paraffins.8,9 In normal paraffins, CN increases with the number of carbon atoms in the molecule. For naphthenic compounds and iso-paraffins the CN falls between those of aromatics and w-paraffins. In iso-paraffins, the CN decreases as the degree of branching increases.10... 

The quality of diesel fuel is measured using the cetane number, a measure of the tendency of a diesel fuel to knock in a diesel engine, and the scale, from which the cetane number is derived, is based on the ignition characteristics of two hydrocarbons (1) n-hexadecane (cetane) and (2) 2,3,4,5,6,7,8-heptamethylnonane. 

Does the Diesel engine have engine knock problem Why ... 

Together, water and SO can combine to form sulfur-bearing acids. These acids can accumulate to initiate corrosive wear, oxidation of lubricating oil, and the formation of piston lacquer deposits within the combustion chamber. Engine deposits can result in operability problems such as preignition knock, dieseling, and wear. 

The use of EDS/DF-2 fuel blends in utility diesels provides an acceptable alternative of conventional petroleum-based fuel operation. A blend ratio of approximately 66.7 percent EDS and 33.3 percent DF-2 can be used without engine knocking at an AMT of 110° F. At an AMT of 150° F this ratio can be extended to 75 percent EDS. The major impact of the use of EDS blends appears to be an increase in the particulate emissions rate. 

Beyond doubt, relatively little is known about the oxidation chemistry of aromatics, despite the increasing use of BTX (benzene, toluene and xylene) aromatics for improving the anti-knock behaviour of internal combustion engines. Further, the problem of polyaromatic hydrocarbons (PAH) associated with soot particles which originate particularly in diesel engines focuses attention on combustion-generated pollution. 

In Chapter 1, it was noted that the Fukushima-Daiichi catastrophe provides a good example of Common Cause events the earthquake knocked out the primary cooling pumps, and the tsunami then knocked out the backup pumps. Copies of the Fukushima-Daiichi P IDs (Piping and Instrument Diagrams) are not available. Therefore, for the sake of discussion it is assumed that there are two sets of pumps three operating pumps (Ol, 02, and 03) driven by electricity and two backup pumps (B1 and B2) that are diesel-powered and that do not require electrical power. The Fault Tree for this assumed set up is shown in Figure 15.28. It consists entirely of and Gates. 

Now comes the earthquake it knocks out electrical power. Hence all three of the operating pumps fail due to the first common cause Electrical Power Failure caused by the earthquake. This is bad, but the backup pumps, which together have a probability of failure of 1 in a 1000, can be trusted to work since they have their own, independent source of power (diesel). But, 40 minutes later, the tsunami disables the backup pumps due to a second common cause sea water flooding. The reactor core continues to generate substantial amounts of heat, but there are no means of removing that heat. 

Compared with petrol and diesel fuels, the combustion of jet fuel takes place, not in a batch reactor, but in an open reactor, thus avoiding the occurrence of knock. Therefore, the problems connected with RON or cetane numbers, such as autoignition, do not impose stringent conditions on the chemical composition of jet fuels. 

The oxidation of hydrocarbons at low temperatures, between 500 and 900 K, is of great importance as these reactions are responsible for the engine knock in spark-ignition engines and the autoignition of diesel fuel in Diesel engines and contribute to the formation of pollutants. 

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